Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
  • C07C37/70—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment
  • C07C37/74—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by distillation
  • C07C37/76—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by distillation by steam distillation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/11—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions increasing the number of carbon atoms
  • C07C37/14—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions increasing the number of carbon atoms by addition reactions, i.e. reactions involving at least one carbon-to-carbon unsaturated bond
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
  • C07C37/70—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment
  • C07C37/72—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by liquid-liquid treatment
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
  • C07C37/70—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment
  • C07C37/84—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by crystallisation

Definitions

• This invention relates to the production of 2,2-(4,4- dihydroxydiphenyl) propane and more specifically to the production of 2,2-(4,4dihydroxydiphenyl) propane of a high degree of purity from phenol and unsaturated hydrocarbons.
• Bisphenol-A (as 2,2-(4,4' dihydroxydiphenyl) propane is known), is conventionally produced by the condensation of two mols of a phenol with one mol of acetone in the presence of an. acidic substance. It can be prepared, however, by other methods also, such as, for in stance, .by the reaction of phenol with substances containing double or triple bonds, such as propadiene (allene) propyne (methyl acetylene), and mixtures thereof, under the influence of a Friedel-Crafts or Lewis acid catalyst such as boron trifluori-de.
• impurities may comprise, for example, higher condensation pro-ducts, containing, for instance, three phenolic nuclei to two radicals of the ketone, and still higher condensation produc-ts in form of resins and tars, and condensation products having a composition similar to, or identical with, that of the 2,2-(4,4-dihydroxydiphenyl) propane, but having diiierent properties (possibly isomers, hemiacetals or similar compounds), and condensation products of the ketone with itself, and high molecular colored substances and others.
• the product may be purified by extraction with hot heptane or similar paratfinic hydrocarbons. Although this process is able to improve the quality considerably, it fails to remove most of the colored substances contained in the crude product, resulting in a finished product which is of low quality regarding color.
• the distillation can be achieved by observing a number of necessary precautions, such as: insuring the complete absence of acidic or alkaline substances and other material such as certain salts, which could act as catalysts in the rapid decomposition of bisphenol to resinous matter; employing a very .good vacuum; employing the shortest possible holding time in the evaporator; preferably using :a thin-surface evaporator, etc.
• necessary precautions such as: insuring the complete absence of acidic or alkaline substances and other material such as certain salts, which could act as catalysts in the rapid decomposition of bisphenol to resinous matter; employing a very .good vacuum; employing the shortest possible holding time in the evaporator; preferably using :a thin-surface evaporator, etc.
• the distillate of even the most carefully distilled bisphenol may contain quantities of a yellow resinous substance, having a slightly lower boiling point than hisphenol, and causing a
• An object of the present invention is to produce 2,2- (4,4-dihydroxydiphenyl) propane of a very high degree of purity which may be determined by a freezing point higher than 156.5 degrees centigrade.
• a further object of the invention is to provide a simple economical method of purifying crude Bisphenol-A containing impurities formed as by-products of the reaction.
• Another object of the invention is to provide a process for the production of Bisphenol-A having a very high degree of purity at a yield essentially the same as that obtained in producing a crude product containing a considerable percentage of impurities.
• Reasoning underlying this invention includes the following. Although it appears plausible to base a purification on the voluntary appearance of crystals of bisphenol, or addition products of bisphenol with phenol, in the course of the condensation, processes using this method of purification suffer from the necessity for separating these crystals as by filtering or centrifuging, in the presence of strong, highly corrosive acids, such as sulfuric or hydrochloric acid, of freeing the crystals of the last traces of such acids as by washing and by working up the mother liquors consisting of excess phenol, water, acids, impurities and bisphenol to recover the valuable ingredients.
• strong, highly corrosive acids such as sulfuric or hydrochloric acid
• Table I shows several of the foregoing described properties when Bisphenol-A, or 2,2-(4,4'-dihydroxydiphenyl) propane, was tested with various solvents.
• the main problem of this invention then is to remove the impurities out of the crude product.
• a partial solution to this problem is in the suggestion of Canadian Patent 551,049 to extract a crude bisphenol by means of hot parafiinic hydrocarbons, preferably heptane. This solution was only partially eifective because, although by this method a considerable portion of the impurities can be removed, another portion, especially that comprising the colored materials cannot be removed economically.
• a problem was to find a solvent which has a much higher purifying ability than the paratfinic hydrocarbons, a solvent which, more specifically, is able to remove the colored impurities as well as the other impurities.
• This solvent should be easily and economically available; it should have a low boiling point in order to permit an easy drying of the extracted product; and, as its most important property, it should have a high dissolving power for the colored materials combined with a low dissolving power for bisphenol. ln searching for such solvent, it was found, however, that these criteria alone are not sufi'icient to define suitable solvents for the purification of Bisphenol-A made by the herein described processes.
• the purity of a Bisphenol A product is determined from the expressed by two criteria, namely, freezing ppint and color.
• the freezing point was taken in the usual manner in a one inch test tube surrounding by an insulating jacket and using a thermometer divided into tenths of a degree, calibrated against an instrument normalized by the Bureau of Standards, with stem correction applied.
• the color was characterized by measuring, in a one-half inch cell of a Spectronic colorimeter, produced by Bausch and Lomb, the relative transparency to light of 350 millimicron wave length of a 50 percent solution of the bisphenol in ethyl alcohol.
• Table I shows, in the first vertical column a number of different solvents so tested, arranged in ascending order of their boiling points, in the second column their boiling points, in the third column the solubility of bisphenol in them.
• the fourth column shows the solubility in them of a typical and representative resinous material of a brown color isolated from crude bisphenol.
• the sixth, seventh and eighth columns give the freezing point, the light transmittance, and the yield of product obtained by pouring grams of a commercial grade of Bisphenol-A, having a freezing point of 147.1 degrees centigrade, and a light transmittance of a 50 percent alcoholic solution thereof of 3.2, into 200 grams of solvent, agitating the mixture for 3 minutes, separating the liquids from the solids in a Biichner filter with suction, washing the crystal in the filter with another 100 grams of solvent, drying the solid in vacuum, by gradually heating up to the melting point, and measuring the freezing point and light transmittance as previously described.
• the commercial bisphenol was one that had had impurities distilled off from it and had been solidified as described in Example 4.
• solubility should be within certain limits; Solvents in which the solubility, under the conditions applied, is less than 0.1 percent, give in general a good yield but a low quality of the extracted bisphenol as demonstrated by freezing point and light transmittance. The reason may be that their low solvent power for the bisphenol prevents them from penetrating into the crystal interstices. On the other hand, the solubility of the bisphenol should not exceed a certain upper limit, because otherwise too much of it is dissolved with the impurities, resulting in a low yield.
• oxygen containing solvents such as ethanol, acetone, acetic acid, etc. have a low degree of suitability, mainly because of their high solvent power for Bisphenol-A.
• Paraflinic and cyclo-paraflinic hydrocarbons and their derivatives have also a low degree of suitability, by reason of their low solvent power for impurities.
• Some of the low boiling chlorinated hydrocarbons combine a low solvent power for the bisphenol with a high solvent power for the resins, and thus are well suited for the purpose.
• aromatic hydrocarbons show the best combination of vapor pressure, solvent power for the bisphenol and for impurities.
• benzene is the most suitable by reason of its high vapor pressure, low solvent power for the his phenol, high solvent power for impurities and ready availability.
• the solvents which were found, as a result of these experiments, to be well suited for the purification of the bisphenol are far superior in this respect to paraffinic hydrocarbons suggested previously for that purpose.
• Example 1 One hundred grams of Bisphenol-A of the properties of commercially available material, in flake form, having a freezing point of 153.9 degrees centigrade and a relative transparency of 28 percent were mixed in a beaker with 200 grams of heptane, heated under constant agitation to 70 degrees centigrade and kept at this temperature under continued agitation for 3 minutes. The mixture was then filtered through a Biichner filter under vacuum, washed with 100 grams heptane, dried by heating it under vacuum of approximately 1 millimeter of mercury to its melting point, and the product resulting was then tested. The freezing point was found to be 155.4 degrees centigrade and the relative transparency was 38.5 percent.
• Example 2 The same material was subjected to a treatment exactly the same in all details as in Example 1, except that instead of heptane, benzene was used and the temperature was degrees centigrade instead of 70 degrees centigrade. This product showed a freezing point of 156.0 degrees centigrade and a relative transparency of 64.8 percent. The total impurities were thus reduced from 7.2 mol percent to 2.9 mol percent, giving about 40 percent improvement in the removal of all impurities over that effected by heptane, while the coloring materials were reduced in the ratio from 72 to 35.2, showing an improvement of the color removal of 350 percent effected by benzene over that effected by heptane.
• Example 3 Example 2 was repeated in exactly the same form except that instead of benzene, methylenedichloride was used. A freezing point of 155.8 degrees centigrade and a color of 61.0 percent relative transparency were obtained.
• This example and similar experiments with other solvents establish that the solvents selected according to this invention, and specifically methylenedichloride, are better extracting agents for impurities in general and especially for the colored impurities, than the heptane suggested before, andthat a product of better quality is obtained by the present invention.
• Example 4 A sample of the same crude bisphenol with which Examples 1, 2 and 3 had been carried out, was melted, poured into a glass tray in a layer about 1 inch deep and permitted to crystallize in the course of about 10 minutes. It was then broken up, ground on a rotating knife mill and screened through a 10 mesh screen. The melting point of this product remained unchanged at 153.9 degrees centigrade and the color increased to a relative transparency of 20 percent. After extracting it with heptane exactly as described in Example 1, its freezing point was found to be 156.4 degrees centigrade and its relative transparency was 48 percent, indicating a decided improvement over the figures obtained in Example 1, in which the same material had been run after cooling on flaking rolls.
• Example 5 A sample of the same material as that used in Example 4 was extracted with benzene under otherwise the same conditions as in Example 2. It gave a freezing point of 156.6 degrees centigrade and a relative transparency of 72.4 percent. Comparison of Example 5 with Example 4 shows again the superiority of benzene over heptane. Comparison of Example 4 with Example 1, and of Example 5 with Example 2 shows that the result of the extraction of the slowly cooled material is better than of a material cooled fast, as for instance, on flaking rolls.
• Example 6 This .example served to show the eifect of distillation upon crude bisphenol.
• a sample of the same crude bisphenol which was used in all previous examples was distilled in glass equipment, with the shortest possible holding time, under a vacuum of less than 1 millimeter of mercury.
• the distillate had a freezing point of 155.1 degrees centigrade and a relative transparency of 39 percent.
• a distillate so obtained preferably a product obtained after a double distillation, in which the more volatile materials are distilled off the Bisphenol-A and the Bisphenol-A is then distilled off the product of lower volatility, under vacuum, can be further improved by extraction, and extraction with the solvents as defined in this invention is more effective than extraction with paraffinic hydrocarbons.
• Example 7 The distillate of Example 6 was permitted to crystallize slowly in a glass tray, was then ground and screened through a 10 mesh screen and the grains were extracted with heptane exactly as described in Example 1. The freezing point was 156.4 degrees centigrade and the relative transparency 50.3 percent.
• Example 8 The grains prepared as in Example 7 were extracted with benzene exactly as in Example 2. The freezing point was 156.6 degrees centigrade and the relative transparency was 77.1 percent.
• Example 9 Freezing Point Color
• the solvents filtered from the extracted material contain the impurities removed from the crude bisphenol, in solution. These impurities can be isolated and the impurities recovered in concentrated form by several methods such We prefer to Example 10 One thousand and one hundred and ten grams of crude Bisphenol-A having a freezing point of 154.0 degrees Centigrade, were extracted with 1500 grams of benzene, filtered, washed with 200 grams of benzene, extracted again with 1500 grams of benzene, filtered, Washed with 200 grams of benzene and dried. One thousand and twenty-eight grams of product having a freezing point of 157.0 degrees centigrade were obtained. The combined benzene solution was evaporated and left a residue of grams of resinous material. The quantity of bisphenol in the residue was too small for detection.
• the removal of the impurities by extraction may result in a loss of weight of 10 to 15 percent or more of the impure product, depending upon the percentage of impurities originally present. This weight loss might make the process, as described so far, economically unattractive, if it were not for an entirely unexpected observation which also forms part of this invention.
• Example 11 shows the production of 2,2-(4,4'-dihydroxydiphenyl) propane from the reaction of phenol with propyne (methyl acetylene) in the presence of boron trifluoride (Bl- Example 11
• boron trifluoride Bl- Example 11
• the residue was 2,2-bis(parahydroxyphenyl) propane in 79 percent yield, based on the weight of propyne added. It contained impurities which can be partially removed by distilling ofi the Bisphenol-A, but some resin will still be present in the Bisphenol-A so produced.
• the above reaction for producing Bisphenol-A may also be carried out by the use of other Friedel-Crafts or Lewis acid catalysts, such as sulfuric acid, phenol sulfonic acid, active clays, hydrogen chloride, hydrogen fluoride and 9 halides of boron, aluminum, zinc, tin, and iron, such as ferric chloride, etc.
• Lewis acid catalysts such as sulfuric acid, phenol sulfonic acid, active clays, hydrogen chloride, hydrogen fluoride and 9 halides of boron, aluminum, zinc, tin, and iron, such as ferric chloride, etc.
• propadiene can be used, or mixtures of the two acyclic hydrocarbons can be used to obtain the desired 2,2-(4,4.- dihydroxydiphenyl) propane.
• the overall mole ratio of phenol to propyne or propadiene should be between about 2:1 and about 15:1 and the amount of catalyst to use should range-between about 0.01 percent and about 3.0 percent by weight of the phenol present.
• Example 12 herein shows our preferred method of preparing 2,2(4,4'-dihydroxydiphenyl) propane of unusual- 1y high purity by means of separating the impurities.
• Example 12 Eighty parts/time of phenol and 1.2 parts/time of recycled by-product resin, recovered by separation of the by-product resin from the bisphenol product and further reaction of by-product resin with phenol in the presence of BF have continuously dissolved in them about 1 part/ time of boron trifluoride and about 5.5 parts/time of propyne, and are continuously fed to the first of three jacketed agitated reactors arranged in series and kept at 50 degrees centigrade. To the reacted material, leaving the third reactor, 130 parts/time of phenol are continuously added with agitation. The mixture is fed to the 10 the said first of three agitated reactors recited at the be ginning of the example.
• anhydrous hydrogen chloride may also be used as a catalyst.
• dihydroxydiphenyl propane as of 2,2-(4,4'-dihydroxytop of the first of three columns, from which the boron trifluoride and a part of the phenol will be driven off and recovered in a condensing and/ or absorbing system.
• a tarry residue is continuously discharged from the bottom of the third column.
• the distillate is continuously fed into a trough in which an internally cooled cylinder rotates.
• a layer of crude Bisphenol-A, having a freezing point of about 156 degrees centigrade builds up. It is continuously removed by a blade, fed into a grinder, where it is reduced to a size passing through a 10 mesh screen, and fed continuously to a separation zone for the removal of resinous byproduct boiling close to Bisphenol-A.
• the separation of the by-product resin may be accomplished by crystallization.
• the material is preferably crystallized by means of about 50 parts/ time of benzene.
• a product of acceptable freezing point and light transmission e.g., a freezing point of 1568+ degrees centigrade and a light transmittance as defined above of 75+ percent, are obtained.
• the benzene containing the extracted impurities is recovered in a continuous atmospheric distillation to leave about 1.2 parts/time of by-product resin to be treated in accordance with the improvement of this invention and to be recycled to the reactors.
• the 1.2 parts/time of by-product resin are fed into the first of two agitated reactors arranged in series where about 3.6 parts/time of phenol and about 0.1 part/time of BF are added and maintained at a temperature of between about 40 and about 150 degrees centigrade until reaction has essentially ceased.
• the reacted by-product material is then discharged, recycled, and charged, along with the phenol and propyne feed materials, into diphenyl) propane itself, may also be used in the process of this invention.
• saturated chlorinated aliphatic solvents are dichloromethane (methylene chloride), chloroform, carbon tetrachloride, 1,2-dichloroethane (ethylene dichloride), 1,1-dichloroethane, 1,1,1- trichloroethane, 1,1,2-trichloroethane, l-chloropropane, Z-chloropropane, 1,1-dichloropropane, 1,2-dichloropropane,1,3-dichloropropane, 2,2-dichloropropane, l-chlorobutane, 2-chlorobutane, tert.-butylchloride, dichlorobutane, l-chloropentane, 2-chloropentane, S-chloropentane, 2 chloro 2 methylbutane, l-chloro-Z-methylbutane, 1- chloro-3-methylbutane, 2-chlorohexane, 2-
• a process for the recovery of a purified 2,2-(4,4'- dihydroxydiphenyl) propane from its crude reaction product produced by the condensation of phenol with a compound selected from the group consisting of propadiene, propyne, and mixtures thereof including the steps of (1) removing the more volatile materials from the 2,2-(4,4'- dihydroxydiphenyl) propane, (2) vacuum distilling the 2,2-(4,4'-dihydroxydiphenyl) propane from materials less volatile in it, and (3) separating the distilled 2,2-(4,4'- dihydroxydiphenyl) propane from its impurities with a solvent selected from the group consisting of benzene, toluene, xylene, methylene chloride, ethylene dichloride, and trichloroethylene, whereby substantially pure 2,2-(4,4- dihydroxydiphenyl) propane and a solvent solution of separated impurities are produced.
• a process for the recovery of 2,2-(4,4-dihydroxydiphenyl) propane having a freezing point greater than 156.5 degrees centigrade from its crude reaction product produced by the condensation of phenol with a compound selected from the group consisting of propadiene, propyne, and mixtures thereof including the steps of (l) distilling the more volatile materials from the 2,2-(4,4'- dihydroxydiphenyl) propane, (2) vacuum distilling the 2,2-(4,4-dihydroxydiphenyl) propane from materials less volatile in it, (3) separating the distilled 2,2-(4,4'-dihydroxydiphenyl) propane from its impurities with a solvent selected from the group consisting of benzene, toluene, xylene, methylene chloride, ethylene dichloride, and trichloroethylene, whereby substantially pure 2,2-(4,4- dihydroxydiphenyl) propane and a solvent solution of separated impurities are produced, (4) recovering the separated impurities from the solvent, and (5) recycling the said impur
• a process for the recovery of 2,2-(4,4'-dihydroxydiphenyl) propane having a freezing point greater than 156.5 degrees centigrade from its crude reaction product produced by the condensation of phenol With a compound selected from the group consisting of propadiene, propyne, and mixtures thereof, including the steps of (1) distilling the more volatile materials from the 2,2-(4,4-dihydroxydiphenyl) propane, (2) vacuum distilling the 2,2- (4,4'-dihydroxydiphenyl) propane from materials less volatile in it, (3) separating the distilled 2,2-(4,4-dihydroxydiphenyl) propane from its impurities With a solvent selected from the group consisting of benzene, toluene,

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Cited By (14)

Citations (2)

• 0
  • NL NL301690D patent/NL301690A/xx unknown
• 1962
  • 1962-12-31 US US248279A patent/US3290391A/en not_active Expired - Lifetime
• 1963
  • 1963-12-12 GB GB49191/63A patent/GB1071487A/en not_active Expired
  • 1963-12-30 DE DE1963H0051257 patent/DE1493816B2/de active Granted

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